As I see it, questions about the vision boil down to whether we want to incorporate the Solar System in our economic sphere, or not. Our national policy, declared by President Bush and endorsed by Congress last December in the NASA authorization act, affirms that, "The fundamental goal of this vision is to advance U.S. scientific, security, and economic interests through a robust space exploration program." So at least for now the question has been decided in the affirmative.

A long term vision for humanity and its offspring must include the idea of stewardship, of gardening, nurturing and protecting the worlds we inhabit. When we travel, it will not be just ourselves we take with us, but our biosphere as well. It is therefore critical that we protect our biospheres...even more so to give us time to get off, and a place to come back to. In 2004, before becoming NASA administrator, Mike Griffin had some outstanding words on the subject, and what needs to be done:http://www.spaceref.com/news/viewsr.html?pid=12483"Mister Chairman and members of the subcommittee, thank you for giving me this opportunity to comment on the greatest natural threat to the long-term survivability of mankind, an asteroid impact with the Earth. "

06 April 2006

From: http://www.spaceref.com/news/viewpr.nl.html?pid=19462ANU astronomers have discovered a nearby solar twin which may shed light on the search for planets that are similar to Earth and that may even support life.HD98618 is only the second star found so far that is almost identical to the Sun in age, size, temperature and chemistry, according to the researchers Dr Jorge Meléndez, Ms Katie Dodds-Eden and Mr José Robles, from the Research School of Astronomy and Astrophysics."This solar twin doesn't only have the same mass as the Sun, it was also formed with the same 'chemical recipe'. So this star was equipped in the same way as the Sun to form Earth-like planets," Mr Robles said."Hopefully, as new planet finding techniques are developed and refined, astronomers will find whether HD98618 hosts terrestrial planets, which may even contain life."HD98618 lies a mere 126 light-years away in the northern constellation of Ursa Major (the 'Big Dipper'). It is bright enough to see in binoculars, but only in the Northern Hemisphere.The researchers believe that HD98618 is about four billion years-old, about 10 per cent younger than our own Sun. Its chemical properties are almost identical to the Sun and to the other closest Sun twin, a star known as 18 Scorpii, which was discovered a decade ago."It means that hypothetical terrestrial planets around this solar twin may have had enough time to develop some kind of complex life, assuming the time-scale for complex life formation is similar to Earth's," Dr Meléndez said.

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Hopefully humanity will achieve the ability to travel beyond our system. When we do, it will be useful to have a plan for how to survey and expand. Even if we are "Transhuman" in this timeframe, we will likely still want to watch systems similar to our own (in the same way we watch avian flu to ensure it does not become virulent), and it is unlikely that the tyranny of distance will be completely eradicated even if we achieve radical life extension. Resources are likely to always constrain our ambitions, and we will have to choose what gets priority.

Therefore we should at least start to think about our priority for exploration. Good initial candidates might be picked from the SETI projects top most habitable stars, which were lately articulated by Margaret Turnbull ( http://www.space.com/scienceastronomy/060221_habstars.html ). We may also want to give thought to the structure of the search, not unlike previous exploration missions were fleets travel together for a time before splitting up, to circuits of travel, and to starts that lie in a plane and can use common navigational references.

04 April 2006

It has often been said that, if the human species fails to make a go of it here on the Earth, some other species will take over the running. In the sense of developing intelligence this is not correct. We have or soon will have, exhausted the necessary physical prerequisites so far as this planet is concerned. With coal gone, oil gone, high-grade metallic ores gone, no species however competent can make the long climb from primitive conditions to high-level technology. This is a one-shot affair. If we fail, this planetary system fails so far as intelligence is concerned. The same will be true of other planetary systems. On each of them there will be one chance, and one chance only. (Hoyle, 1964)

I think this is the credible viewpoint, but I don't think absolute pessimism is in order. Given a long enough time scale (hundreds of millions of years) after a demise of human life, the Earth might replentish fossil fuel supplies. We may have created essentially new stores of high grade materials, already concentrated along with some archeology that might well catapult a successor civilization.

But the goal is to spread our memes and our genes, and that means we must get off world, start replicating, remove the single point of failure, find new energy sources, and protect and spread our biosphere.